Method and apparatus for assembling blades onto a blade support



Sept. 8, 1970 N E. DOVEY 3,327,123

METHOD AND AI PARATUS FOR ASSEMBLING BLADES ONTO A BLADE SUPPORT FiledMarch 35, 1968 4&274

FIG. 7

NVENTOR.

I \j 36 e4 NORMAN E, DOVEY BY FIG.8 F|G.9

ATTORNEYS United States Patent 3,527,123 METHOD AND APPARATUS FORASSEMBLING BLADES ONTO A BLADE SUPPORT Norman Edward Dovey, PompanoBeach, Fla, assignor to Dovey Manufacturing Company, Anderson, Ind., acorporation of Indiana Filed Mar. 25, 1968, Ser. No. 715,653 Int. Cl.B26d 7/26 US. Cl. 76-107 16 Claims ABSTRACT OF THE DISCLOSURE Animproved method and apparatus for assembling cutting blades onto theouter surface of a blade support. The method includes: forming anelongated groove on the outer surface of the support, positioning theblade in the groove; and, force fitting into the groove an elongated,resiliently deformable member having a plurality of closely spacedoutwardly extending surface portions on opposite longitudinal sidesthereof. In the preferred embodiment, the deformable members are of coilsprings and two of them are utilized.

The present invention is directed toward the cutting art and, moreparticularly, to a method and apparatus for assembling a cutting bladeor knife onto a knife support.

The invention is especially suited for assembling steel rule knives ontothe outer periphery of a rotary knife support of the type adapted torotate against a rotary anvil so that cardboard sheets passing betweenthe anvil and the knife support will be out according to the arrangementof the knife and it will be described with particular reference thereto;however, it will be appreciated the invention is capable of much broaderapplication and could be utilized for assembling a variety of types ofknives or blades onto many different supports used in the cutting art.In addition, the invention may be used in supporting various thinmembers edgewise into a groove.

In cutting blanks from cardboard sheets the predominately usedarrangement is to mount rule knives into the outer surface of acylindrical knife support mounted on a rotating shaft. The rule knivesare generally flat metal strips having one longitudinal edgeconstituting a cutting edge and the other edge adapted for securing tothe surface of the knife support. A rotary anvil is spaced radially fromthe knife support and is arranged to cooperate with the knives so thatas cardboard sheets are passed between the anvil and the support theyare blanked or cut in a configuration dictated by the arrangement of theknives. As can be seen, each revolution of the knife support produces anidentical series of cuts or blanks. Consequently, this apparatus isespecially suited for economical mass production of cut cardboardarticles. Additionally, the apparatus is comparatively simple inconstruction and has a low first cost, as Well as, low maintainencecost.

Because of its many advantages, the above-mentioned apparatus has beenwidely accepted as the most suitable apparatus for cutting cardboard.The primary disadvantage of the apparatus is the difficulty ofassembling the knives onto the support. Prior to the present invention,a variety of types of connecting means and methods have been utilizedwith varying degrees of success. For example, one commonly used methodwas to form the knife support with a plurality of segments having matingcontours corresponding to the configuration of the blank to be cut. Thismethod was quite expensive and required precision machining and fitting.Additionally, the number of knife configurations available with any onesupice port was limited. Another method utilized was to form grooves inthe outer surface of the support and connect the knives therein bywedges of deformable material, such as lead. Alteruately, various typesof mechanical clamp and threaded fastener arrangements were utilized.Basically, all of the prior knife mounting arrangements made the job ofmounting and removing the knives relatively diflicult and timeconsuming.

The present invention provides a highly simplified method and apparatuswhich permits the knives to be mounted and removed simply and in aminimum of time. The subject arrangement maintains the knives rigidlyaffixed to the support without the use of any threaded or mechanicalclamp type fasteners.

In accordance with a primary aspect of the present invention an improvedmethod is provided for assembling onto the outer surface of a bladesupport an elongated, fiat cutting blade having first and secondgenerally parallel, opposed side walls joined by a longitudinallyextending cutting edge. The method comprises the steps of (a) Forming,on the outer surface of the blade sup port, an elongated groove havingfirst and second opposed, generally parallel side walls spaced apart adistance substantially greater than the thickness of the blade andjoined by a bottom wall;

(b) Positioning the blade in the groove longitudinally thereof with itscutting edge extending outwardly of the outer surface of the bladesupport and the first side wall of the blade in engagement with thefirst side wall of the groove whereby the resulting longitudinal openspace in the groove has a width a equal to the width of the groove lessthe thickness of the blade;

(c) Providing at least a first elongated resiliently deformable memberhaving a plurality of closely spaced outwardly extending surfaceportions on opposite longitudinal sides thereof, with the transversedistance between the surface portions on opposite sides of the memberbeing slightly greater than a; and

(d) Forcing the member into the open space of the groove to extendlongitudinally thereof with the outwardly extending surface portions onone longitudinal side in engagement with the second side wall of theblade and the portions on the other longitudinal side in engagement withthe second side wall of the groove, whereby forces generated by theresiliency of the member act through the surface portions and clamp theblade in the groove.

In accordance with another aspect of the present invention apparatus isprovided which includes a blade support having an outer surface with anelongated blade receiving groove formed thereon. The groove is definedby first and second generally parallel side walls spaced a givendistance apart and a bottom wall extending between the side walls. Anelongated blade having outwardly facing, generally parallel first andsecond side walls joined by a longitudinally extending cutting edge ispositioned in the groove longitudinally thereof with the cutting edgeextending outwardly of the groove and the first side wall of the bladein engagement with the first side wall of the groove. The blade isfirmly maintained in the groove by at least one elongated, resilientlydeformable member having a plurality of closely spaced outwardlyextending surface portions on opposite longitudinal sides thereof. Thenormal transverse distance between the surface portions on oppositesides of the member is slightly greater than the distance between thesecond side wall of the blade and the second side wall of the groove,and the member is force fitted longitudinally in the groove with theoutwardly extending surface portions on one longitudinal side being inengagement with the second side wall of the blade and the outwardlyextending surface portions on the outer longitudinal side being inengagement with the second side wall of the groove.

Accordingly, a primary object of the present invention is the provisionof a method and apparatus which permits blades to be attached to bladesupports in an extremely simple manner.

Another object of the present invention is the provision of a method andapparatus which allows blades to be connected to blade supports withoutthe use of rivets, threaded fasteners, or other types of mechanicalconnectors.

A still further object of the present invention is the provision of amethod and apparatus which is especially suited for connecting ruleknives to the outer cylindrical surface of rotary knife supports.

A still further object of the invention is the provision of a method andapparatus for connecting a blade to a blade support in a manner whichpermits the blade to be quickly removed from the support without the.use of tools.

These and other objects and advantages of the invention will becomeapparent from the following description when read in conjunction withthe accompanying drawings wherein:

FIG. 1 is an end view, somewhat diagrammatic of a rotary cutter of thetype used for cutting and blanking cardboard sheets;

FIG. 2 is a cross-sectional view taken on line 2-4 of FIG. 1 and showingthe preferred embodiment of the present invention;

FIG. 3 is an end view of one of the connecting members utilized in theFIG. 2 embodiment;

FIG. 4 is a view taken on line 4-4 of FIG. 2;

FIG. 5 is a view taken on line 5-5 of FIG. 2;

FIG. 6 is a pictorial view showing the FIG. 2 embodiment in the processof being assembled or disassembled; and

FIGS. 7, 8 and 9 are, respectively, second, third and fourth embodimentsof the subject invention.

Referring specifically to the drawings wherein the showings are for thepurpose of illustrating preferred embodiments of the invention only andnot for the purpose of limiting same, FIG. 1 shows a side elevation,somewhat diagrammatic, of a rotary knife assembly A of the type utilizedfor blanking cardboard sheets and, with which, the subject invention isespecially suited for use. As shown, the rotary knife assembly Aincludes a cylindrical blade support member 10 which is mounted fordriven rotation on a rotatably driven shaft 12. Knives 14 are mounted onthe outer surface of cylindrical member 10 and are arranged to cooperatewith a rotatable anvil member '16 which is radially spaced from member10. As shown, the anvil 16 comprises a cylindrical member 18 rotatablymounted on shaft 20. The outer anvil surface is preferably formed by aheavy layer 22 of some resilient material such as rubber. As isapparent, with the members arranged as described, a sheet of cardboard24 fed between the support member 10 and the anvil 16 will be cut orblanked in a configuration determined by the layout of knives 14.

The above-described arrangement for the rotary cutting unit A is, so faras described, conventional and of the type predominately used forcutting and blanking cardboard. As previously mentioned, one of theprimary problems of this type of cutter has been the difficulty ofproviding suitable means for releasably connecting the knives to theouter surface of the knife support member 10. The present inventionprovides a highly simplified method for connecting the blades to thesupport member.

As shown in FIG. 2, the knife 14 comprises an elongated, relatively fiatblade having outwardly facing opposed side walls 24 and 26 which arejoined along one edge by a cutting edge 28. The knife 14 is positionedin a longitudinally extending groove 30 defined by a pair of generallyparallel side walls 32 and 34 joined by a lower wall 36. In theparticular embodiment under consideration, groove 30 is machined in anintermediate knife support member 38 which is releasably connected tocylindrical member 10 by a plurality of machine screws 40; however, aswill become apparent, groove 30 could be formed directly in the outersurface of member 10 or, alternately, defined by plate or angle membersconnected to the surface of member 10. As shown, the blade 14' ispositioned longitudinally of the groove 30 with side wall 24 inengagement with side wall 32 of the groove.

Of particular importance to the present invention is the means utilizedto maintain the blade 14 releasably clamped in position in the groove.These means comprise an elongated resiliently deformable member having aplurality of closely spaced, outwardly extending surface portions onopposite longitudinal sides thereof. The member is sized so that thetransverse distance between opposite outwardly extending surfaceportions is slightly greater than the distance between blank surface 26and groove sidewall 34, which distance is denoted by the letter a inFIG. 2. The member is then progressively forced fitted into the groove30 so as to extend longitudinally thereof. This causes the outwardlyextending surface portions to be forced inwardly until they are spaced atransverse distance substantially equal to the distance a. The resilientnature of the member produces forces which act outwardly through thesmall individual area of the surface portions to produce a clampingforce on the blade.

In the preferred embodiment, the member comprises a spring and theoutwardly directed surface portions are thus defined by the outer,diametrically opposed, surfaces of each convolution of the spring. Whenthe spring is force fitted in the groove the outer surface portions ofeach convolution engage the sidewall 34 of the groove and the sidewall26 of the blade along a short narrow band approximately of the nature asshown by the shaded areas 50 of FIG. 5. The multiplicity of smallclosely spaced surface areas 50 produce a relatively high total clampingforce on the blade and make it nearly impossible to withdraw the bladewith the spring member in position. The spring member, however, can berelatively easily removed by progressively pulling it from the groove inthe manner shown in FIG. 6.

Preferably, the spring is inserted into the groove by successivelydriving in a limited number of convolutions i.e. a short section ofspring is first driven in and, thereafter the remaining longitudinallength of the spring is driven in a short section at a time. A varietyof types of tools could be utilized for inserting the springs; however,preferably, the tool should be arranged to prevent permanent deformationof the spring while assuring proper locating. A tool suitable for thispurpose is shown in FIG. 8. As shown, the tool includes a downwardlyextending portion 82 which is sized for easy insertion in the groove 30.The lower end 84 of the tool is shaped to conform to the outer surfaceof the spring. Additionally, a stop 86 is provided to limit the extentto which the tool can be inserted. Consequently, the spring is alwayspositioned at the same depth in the groove and cannot be permanentlydeformed irrespective of the amount of force applied to the tool.

As can be seen from the above, the actual force which must be applied atany one time to insert the spring is relatively small; however, theforce which must be applied to the blade for removal with the spring inposition is extremely high. Additionally, when the spring and blade aresized so as to engage opposite end walls of the groove the inclinednature of the surface areas 50 cause the blade and spring to want tomove longitudinally in the groove when an attempt is made to pull theblade from the groove. This of course cannot happen when there is an endwall of the groove in engagement with the spring and blade and,accordingly, the blade is locked even more firmly into position.

Referring again to the preferred embodiment of FIG. 2 it is seen thattwo springs 44 and 46 are utilized. The springs are preferably of thesame size and, as shown in FIG. 3, have a normal diameter b which isslightly larger than distance a. The use of two springs in a mannershown in FIG. 2 is preferred because the blade is thus engaged at twopoints transverse of its width and it is given greater stability againsttransverse tilting in the groove. Additionally, as shown in FIGS. 2 and5, springs 44 and 46 are preferably of the same hand, that is forexample, both of the springs are coiled clockwise or, both coiledcounterclockwise. This prevents the springs from entering intoengagement with one another and shifting the points at whichthey engagethe blade. This feature can best be seen in FIG. 4 which shows that thecoils of the upper and lower springs cross one another in a diagonalrelationship.

When inserting the second spring 46, a tool similar to previouslydescribed tool 80 is preferably used. The position of the stop 86 isdifferent however so that the second spring cannot be driven into thefirst spring. Additionally, it is believed to be more satisfactory ifthe springs do not engage one another i.e. the lower surface upperspring should be slightly spaced from the top surface of the lowerspring.

Although it is preferred to use two springs of the type and in themanner shown in FIG. 2, it is of course understood that other types ofsprings having less tightly wound convolutions or other types ofelongated resilient members having somewhat similarly arranged,outwardly extending portions could be used.

FIG. 7 shows a second modification of the invention which is similar inall respects to the modification shown and described in FIG. 2, exceptthat the blade 60 has a tab portion 62 which is bent at right angles tothe main blade portion and engages the bottom Wall 36 of the groove. Thetab portion 62 can be continuous along the blade or comprise a pluralityof individual tab sections of any desired longitudinal length. The tabportion assists in the original positioning of the blade in the grooveand, further, assists in preventing the blade from being tiltedtransversely in the groove.

Although less desirable, it is possible to use only one spring memberfor clamping the blade in the groove. Referring specifically to FIGS. 8and 9, two modifications of the invention wherein only one spring isused are shown. In FIG. 8, one spring is positioned along the bottom ofthe groove and in engagement with the sidewall of the blade and thesidewall of the groove. This spring is sufficient to prevent the bladefrom being pulled outwardly of the groove but, does not function as wellas the FIG. 2 embodiment for preventing the blade from being twisted ina clockwise direction as viewed in FIG. 8.

The FIG. 9 embodiment also uses only one spring; however, in thisembodiment a longitudinally extending, generally rectangular member 64is positioned in the bottom of the groove and, preferably, closelyengages both the blade and the side wall of the groove. This member, incombination with a clamping spring, prevents the blade from beingrotated in a clockwise direction.

The invention has been described in great detail sufficient to enableone of ordinary skill in the art to make and use the same. Obviously,modifications and alterations of the preferred embodiments will occur toothers upon a reading and understanding of the specification and it ismy intention to include all such modifications and alterations as partof my invention insofar as they come within the scope of the appendedclaims.

Having thus described my invention, I claim:

1. An improved method of assembling onto the outer surface of a bladesupport, an elongated, flat cutting blade having a thickness defined byfirst and second opposed, generally parallel sidewalls joined by alongitudinally extending cutting edge, said method comprising the stepsof (a) forming, on the outer surface of said blade support, an elongatedgroove having first and second opposed sidewalls spaced apart a distancesubstantially greater than the thickness of said blade and joined by abottom wall;

(b) positioning said blade in said groove longitudinally thereof withits cutting edge extending outwardly of said outer surface of said bladesupport and one of said sidewalls of said blade in engagement with thefirst sidewall of said groove whereby the resulting longitudinal openspace in said groove has a width a substantially equal to the width ofsaid groove less the thickness of said blade;

(0) providing at least a first elongated resilient deformable memberhaving a plurality of closely spaced outwardly extending surfaceportions on opposite longitudinal sides thereof, the transverse distancebetween said surface portions on opposite sides of said member beingslightly greater than a; and

(d) forcing said member into the open space of said groove to extendlongitudinally thereof with the outwardly extending surface portions onone longitudinal side in engagement with the second sidewall of saidblade and the portions on the other longitudinal side in engagement withthe second sidewall of said groove, whereby forces generated by theresiliency of said member act through said surface portions and clampsaid blade in said groove.

2. The method as defined in claim 1 including the steps of providing asecond elongated, resilient deformable member formed similarly with saidfirst member and forcing said second member into said open space to restupon said first member and have its outwardly extending surface portionsin clamping engagement between the second sidewall of said blade and thesecond sidewall of said groove.

3. The method as defined in claim 1 wherein said first member providedcomprises a coil spring.

4. Apparatus comprising in combination: a blade sup port having an outersurface; means forming an elongated blade groove on said outer surface,said groove defined by first and second generally parallel sidewallsspaced a given distance apart and a bottom wall extending between saidsidewalls; an elongated blade having outwardly facing, generallyparallel first and second sidewalls joined by a longitudinally extendingcutting edge, the distance between said sidewalls of said blade beingsubstantially less than the distance between the sidewalls of saidgroove; said blade being positioned in said groove longitudinallythereof with the cutting edge extending outwardly of said groove and thefirst sidewall of said blade in engagement with the first sidewall ofsaid groove; and, at least one elongated, resiliently deformable memberhaving a plurality of closely spaced outwardly extending surfaceportions on opposite longitudinal sides thereof, the normal transversedistance between the surface portion on opposite sides being slightlygreater than the distance between said second sidewall of said blade andthe second sidewall of said groove, said member being force fittedlongitudinally in said groove with the outwardly extending surfaceportions on one longitudinal side being in engagement with the secondsidewall of said blade and the outwardly extending surface portions onthe other longitudinal side being in engagement with the second sidewallof said groove.

*5. The apparatus as defined in claim 4 wherein said first elongatedmember comprises a coil spring.

'6. The apparatus as defined in claim 4 including a second elongatedresilient deformable member formed similarly to said first member andforce fitted in said groove superjacent said first member.

7. The apparatus as defined in claim 6 wherein said first and secondmembers each comprise coil springs.

8. The apparatus as defined in claim 7 wherein said coil springs arewound in the same directions.

9. The apparatus as defined in claim 6 wherein said first and secondmembers are slightly spaced from one another throughout their length.

10. A method of securing a fiat elongated member having side surfacesedgewise into a groove having sidewalls, said member having a thicknesssubstantially less than said groove, said method comprising the stepsof:

(a) placing said member edgewise into said groove to leave an elongatedspace between at least one side surface of said member and one sidewallof said groove;

(b) providing an elongated resiliently deformable member having aplurality of closely spaced outwardly extending portions on oppositelongitudinal sides thereof and having an undeformed width to provide aninterference fit between said one surface and said one sidewall; and,

(c) forcing said elongated deformable member progressively into saidgroove and between said one surface and one sidewall whereby saiddeformable member is deformed and grips at said extending portions bothsaid one side surface and said one sidewall.

11. A method as defined in claim 10 including the additional steps of:

((1) providing a second elongated resiliently deformable member having aplurality of closely spaced outwardly extending portions on oppositelongitudinal sides thereof and having an undeformed width substantiallythe same as said first mentioned deformable member; and,

(e) forcing said elongated deformable member progressively into saidgroove and over said first-mentioned deformable member.

112. A method as defined in claim 11 wherein said deformable members areeach coil springs.

13'. A method as defined in claim 12 wherein said coil springs have thesame spiralled convol-utions.

14. In a cutting device including a thin knife with a thickness definedby side surfaces and a cutting edge, a knife support having a knifesupporting groove, and means for holding said knife in said groove, theimprovement comprising: said groove having a width greater than thethickness of said knife, and a coil spring-like member force fitted intosaid groove along one of said side surfaces, said spring having anundeformed diameter to provide an interference fit with one of said sidesurfaces and said groove.

15. The improvement as defined in claim 14 including a second coilspring-like member overlying said first member and having a forced fitbetween said one side surface.

16. The improvement as defined in claim 15 wherein said coil spring-likemembers have the same spiralled convolutions.

References Cited UNITED STATES PATENTS 1,398,474 11/1921 Strawn 83348 X3,041,752 7/ 1962 Evans 2'87-126 X 3,196,724 7/1965 Frank 83-583 X3,277,756 10/ 1966 Des Jardins et a1. 83-698 X FOREIGN PATENTS 1,073,147 6/ 1967' Great Britain. 687,691 2/1953 Great Britain.

WILLIAM S. LAWSON, Primary Examiner US. Cl. X.R. 83-698; 287-126

